Mat 21:28 But what do you think? A man had two sons; and he came to the first, and said, Son, go work to day in my vineyard.
Mat 21:29 He answered and said, I will not: but afterward he repented, and went.
Mat 21:30 And he came to the second, and said likewise. And he answered and said, I [go], sir: and went not.
In this parable (or "analogy," which is what "parable" means in Greek), Christ ties together the three aspects of the physical realm, thoughts, actions, and relationships. And beneath it all, the hidden realm of spirit.
Right and wrong flow from relationships, here, the relationships between father and son. Relationships are the basis of feeling and emotion. Feeling lead to thoughts (in this case words), and then thoughts lead to actions.
What feelings cause one son to verbally reject his father's command but later go and do what was asked? The son thinks of himself first, but of his relationship at last. This causes him to act correctly.
The second son thinks of the relationship first, telling his father what he wants to here, but he thinks of himself last, doing what he pleases.
Christ blends several ideas together here. First, his idea of what (and who) comes first and what and who comes after. Remember, Christ said that the first shall be last and the last first.
Here we have two sons, the first (protos) and the second. We also have two choices. The first is a choice about what to say and the second a choice about what to do. The first son says the wrong thing then does the right thing. The second say the right thing and then does wrong thing.
In this story, Christ puts words (the mental world) before action (the physical world). But thoughts change. We are not responsible for every thought we have. We are responsible for the last thought we have, the one that leads to action.
"Think" is dokeô, which means "to expect," "to think," "to suppose," "to have an opinion," "to pretend," "to seem," and "to be reputed."
"Go" is from hupagô, which means "to lead," "to bring under," "to withdraw," "to take from beneath," "to go away," "to retire," and "on with you."
"Work" is from ergazomai, which means "to work," "to labor," "to work at," "to make," "to perform," "to work at," "to cause," and "to practice."
"Repent" is from metamelomai (metamellomai), which means "to feel repentance," "to repent a thing," "to change one's purpose or conduct," and "to feel regret."
"Went" is from aperchomai, which means "go away" and "depart from." It can mean to depart from one place and arrive at another.